vba - Msg if box if checked - but not if unchecked - vba

Question

I am trying to write code for a message to pop up if a checkbox is checked. My spreadsheet has a LOT of checkboxes, and I only want it to do this for the checkboxes in column H. I believe the best way may be to assign a macro to all checkboxes using vba using something like the following code (Except this is not working):
ActiveSheet.Shapes.Range(Array("h9:h89")).Select
Selection.OnAction = "Sheet4.Checkbox"
The second problem I have is that I only want the message to pop-up when it is checked, not when it is unchecked. The following works when the macro is assigned mannually, but for both checking and unchecking. The commented out sections are examples of some of the things I have tried. I believe they are ActiveX checkboxes.
Sub Checkbox()
' Dim rangeVar As Range
'
' rangeVar = ("h9:h89")
'
'With rangeVar
' If WorksheetFunction.Or(.Cells) = True Then
MsgBox ("Are you sure you want to check this box?")
Exit Sub
' End If
'End With
' Dim chk As Checkbox
'
' For Each chk In rangeVar
' If chk.Value = True Then
' MsgBox ("Are you sure you want to check this box?")
' Exit Sub
' End If
' Next chk
End Sub
Thank you!

Answer 1

Assigning the action:
Sub AssignClicks()
Dim cb
For Each cb In ActiveSheet.CheckBoxes
If Not Application.Intersect(cb.TopLeftCell, _
ActiveSheet.Range("H:H")) Is Nothing Then
cb.OnAction = "Sheet1.ClickedIt"
End If
Next cb
End Sub
In the sheet code module:
Sub ClickedIt()
Dim cb As CheckBox
Set cb = Me.CheckBoxes(Application.Caller)
If cb.Value = 1 Then
MsgBox "checkbox at " & cb.TopLeftCell.Address() & " is checked"
End If
End Sub
...or you can assign the action to all of your checkboxes and use code in ClickedIt to determine whether the current checkbox is in Col H.